Measure current through HK4100F-DC5V-SHG relays

[geerlingguy]

With six strands of 16' LED lights hanging off the Pi, even if we assume only one color switched on at a time... I wonder if we might run into current limits for these little relays.

I need to measure the current going through these things. It would be quite annoying to have to do a last-minute audible if the relays aren't capable of switching / sustaining a load with all the light strips attached.

Originally I was worried the Cat6 cabling (if 23 AWG) could be hitting a current limit as I don't think you're supposed to put more than 6A through a single leg. But now I'm worried we might need higher capacity relays!

Specs for this relay: https://abra-electronics.com/electromechanical/relays/pcb-mtg-1a-2a/hk4100f-dc5v-shg-relay.html

[geerlingguy]

I created a light.py script that lets me easily manage individual lights. To use:

sudo systemctl stop light-control
./light.py off

And I can set whatever color so I can manage the relays for current measurement.

[geerlingguy]

So... before I even do that I want to validate we can hang larger relays off the smaller relays. We might need to order 110 of these 4-channel 30 VDC 10A relays...:

[geerlingguy]

Documentation on Sunfounder's board, which seems to be configured similarly: http://wiki.sunfounder.cc/index.php?title=2_Channel_5V_Relay_Module (I have one on hand)

[geerlingguy]

This setup works, thankfully:

Pinout, for reference: https://docs.google.com/spreadsheets/d/1U3z0Gb8HUEfCIMkvqzmhMpJfzRqjPXq7mFLC-hvbKlE/edit#gid=0

[geerlingguy]

Chuck ordered the new relays, hopefully they (and the HATs) come in time... heck if the HATs don't come, we could just wire straight up to these relays, we'd just need to change up the software a bit for light control.